I'm a bit confused because the study counts SF, Silicon Valley and SF Mid-Peninsula without defining them well, and there's no mention of South Bay at all, unless that's what they're referring to as SV.
EDIT: It doesn't seem like SV is being used as an aggregate term, since there's more absolute growth happening in SF and SF Mid-Peninsula than in SV.
EDIT2: Unless I'm terrible at reading charts and tables, it looks a lot like San Francisco hit 72,205 in 2015, not 76,200.
If I understand correctly, you misread that. (Alternately, I misread it.) I think it said that Boston had 7% year-on-year growth of tech jobs, not that Boston had 7% of the country's tech job growth.
San Francisco: +21% 59,600 -> 72,200
Silicon Valley: +7.2% 229,200 -> 245,800
Oakland/East-Bay: +11.8% 50,600 ->56,600
SF Mid-Peninsula: +5.0% 45,600 -> 47,900
Boston: +3.1% 149,700 -> 156,000
Austin: +7.8% 74,400 -> 80,200
[0] page 4: http://www.us.jll.com/united-states/en-us/Research/US-Tech-E...
Edit: Added Mid-Peninsula and East Bay to complete SF Bay Area. Total Bay Area Tech Jobs in 2015: 444,500
Edit 2: Corrected typo, as pointed out, my bad. SF 72,200